My goal for several months has been to make an electronic greeting card that is like the ones you can buy–“Press Here” for the action (in this case, just simple LEDs), no visible battery or circuitry or clip. I know that the hidden battery means it will only work as long as that battery is alive, but I just wanted to see if I could do it. And today I did!
My materials: cardstock; copper tape; scotch tape; a few surface mount RGB LEDs (they light up red and they are the biggest surface mount ones I have, and since I was wanting to avoid LED frustrations, I chose the big ones; in the future, I’d use the smaller ones that are cheaper); a small coin cell battery (CR1225, which at 12mm is smaller than the ones I usually use but I had a bunch because of a mistake order I made earlier this year and in this case, smaller is better), and patience.
First, I absolutely messed up. I had never made a switch before, so I botched that a few times. This is a picture of the circuit that ended up working, which could be prettier than it is but I just kept playing with the same paper and tape and when it worked, I decided to just use it instead of starting over. The part that has the “switch” is just folded over but you need to push on it to make enough of a connection for the LEDs to light up, which is the whole idea. All of what is shown below is now taped behind the picture above, so it is hidden. I taped it in the folded position, because it needs to be pushed in order to connect enough to work. The battery is taped on, with the copper tape below and then the piece that comes on the top of it folded over on itself before taped down (so that the conductive side that is not sticky is touching the battery).
If/when I do this again, I will make a better design for the switch. But I feel pretty happy with it overall. It works! I was intimidated by switches and also by trying to make a switch and then lights in parallel–I don’t know why, since it ended up being easy, but I was.
Now I’m hoping to get back into my Scratch/Arduino/Littlebits adventures. I needed a few days off from that, but I feel ready to try to tackle it again.
One thing I realized is that I need to have a Makerspace in my house, and it needs to be inaccessible to my cats. One of my cats managed last night to sniff open a not-quite-closed plastic bin, drag out a length of copper tape, and attempt (unsuccessfully, thank goodness) to eat it. And one cat came over today while I was working and tried to steal some copper tape backing from the trash can next to me. They are obsessed with the copper tape! I’ve been working in the living room and trying to make things cat-friendly after I stop working, but they are crafty!
Update: Kept playing and made this, which would possibly be a fun birthday card. I used a Lilypad push button switch for the switch, and 4 surface-mount green LEDs. I tried adding a red LED for the cherry on top, but when I did that, the green ones went dim and the red one was really bright, so I did something wrong there.